Three people have been arrested today in connection with last night's violence in Portadown Co Armagh.
Around 100 people hurled petrol bombs, fireworks and bricks at police.
It is thought that loyalists may be behind the attack.
Superintendent Jason Murphy said that the rioters were intent on only hurting the officers but it has affected the whole community.
"This is the loyalist community acting within their own community, and the only people that they're damaging are actually their own people," he said.